Devices for sourcing digital video data are known, for example video players like DVD players or set top boxes. A further example is the Blu-ray Disc (BD) system, for example described in US2006/0143666A1 and ref [2]. The source device is to be coupled to a display device like a TV set or monitor. Image data is transferred from between the devices via a suitable interface system, preferably a high-speed digital interface like High Definition Multimedia Interface (HDMI, see ref [1]). The source device processes video data according to the display capabilities of the display device. Alternatively, the processing may be performed in the display device itself.
WO2006/136989 describes displaying input video data, comprising video data placed in a video plane and overlay data placed in an overlay plane. The video plane is shifted compared to the overlay plane so as the overlay plane does not occult the video plane. The resulting shifted video plane and the overlay plane are mixed for generating output data content. The video data which has active video content has an aspect ratio that differs from the aspect ratio of the output content; the remaining area is usually rendered to be black or gray, and is called black bar area. In particular the device shifts the video plane so that the overlay data substantially is in the black bar area.